Remote-controlled insertion of sheathing in inaccessible manifolds and junctions

ABSTRACT

The new, remote-controlled installation of sheathing into inaccessible manifolds and junctions from subsidiary into main piping makes it possible to repair damaged intersections cheaply, rapidly and reliably, without the intersection having to be exposed by excavation. An application device (1), which is installed on a pipe-repairing machine, makes insertion of a lost sheathing (4) into the subsidiary piping (8) possible. The cavity (12) which comes about in this way between the sheathing (4) and the damaged part is subsequently sprayed with specially suited sealing mass by means of a high-pressure nozzle (13).

This application is a continuation of U.S. application Ser. No.07/619,094 now abandoned filed Nov. 28, 1990.

In manifolds and junctions, for example in main and subsidiary piping,damage of the intersection frequently comes about, especially inwater-pipes. This is mainly caused by corrosive or erosive components inthe sewage water. The intersections damaged in this way represent agreat risk for the ground water and thus for the drinking water ofentire regions, because in this way uncontrolled, large amounts ofdangerous sewage water can seep into the ground. For this reason,fissures or damage which have been established in manifolds or junctionsare to be repaired as soon as possible.

Repairs to manifolds and junctions cannot be carried out with simplemeans, above all when the pipes have such small diameters that they areinaccessible. Up to now, there was no other option but to expose thedamaged spot through excavation and to replace the pipe elements whichhad been damaged. There is the possibility of spraying the damaged areaswith a special sealing gel, but this gel tends to become brittle andthus porous due to the formation of hairline cracks as soon as theground water level drops, for example due to the time of year; thissolution is therefore not to be recommended. The new remote-controlledinstallation of sheathing in inaccessible manifolds and junctions hasbeen derived from a similar method of repair for pipes which has alreadybeen patented by the same inventor (Swiss patent application number3808/87-7) and has already been used successfully. For this patent, aremote-controlled pipe-repairing machine is also used advantageously,which has also been patented by the same inventor and has daily provenits worth in hard use (Swiss patent application no. 1222/87-0). Theremote-controlled installation of sheathing for manifolds and junctionsis the logical further development of this invention.

The following are shown:

FIG. 1a is an end elevation al view of a sheathing to be installed inaccordance with the present invention;

FIG. 1b is a perspective view showing the sheathing of FIG. 1;

FIG. 2a is a partially cutaway cross-sectional view showing anapplication device in accordance with the present invention approachingthe junction of a subsidiary or branch piping and the main piping;

FIG. 2b is a partially cutaway cross-sectional view showing theapplication device inserted into the branch piping of FIG. 2a;

FIG. 3 is a partially cutaway cross-sectional view of the junction withthe application device removed;

FIG. 4 is a partially cutaway cross-sectional view of the junction witha sealing mass injected into the damaged portion of the piping;

FIG. 5 is a block diagram of a conventional pipe-repairing machine; and

FIG. 6 is a cross-sectional view corresponding to FIG. 2b showing thecross-section of the main piping in its entirety.

The application device 1 (FIG. 2) consists principally of a bent screen2 and a pipe-shaped, so-called balloon 3, which protrudes from thelatter and essentially corresponds to an inflatable rubber hose. Thesheathing 4 (FIG. 1) is now slipped over the balloon 3. This sheathinghas a longitudinal slit and is compressed in such a way that the walls 5overlap. Thus, a diameter 6 can be achieved which is smaller than theinternal diameter 14 of the junction 7 of the subsidiary piping 8 (or ofthe manifold, which is not shown). Thus it is possible to insert thesheathing 4 into the subsidiary piping 8 thanks to the expandableballoon 3, as is shown in FIG. 2. FIG. 2a shows the application device 1with the retracted balloon during the approach to the damaged spotthrough the inaccessible main piping 10, which, as already mentioned, iscarried out by means of a repair machine, and FIG. 2b shows theapplication device 1 with the balloon 3 which has been inserted into thesubsidiary pipe 8. From FIG. 2, it can also be seen that the sheathing 4is pushed into the subsidiary piping 8 until the edge 9 makes flushcontact with the screen 2 pushed onto the main piping 10. Thus, it isguaranteed that on the one hand the sheathing is not pushed too far intothe subsidiary piping 8 and that on the other hand it does not protrudeinto the main piping 10 after the repair work has been carried out, thusreducing its serviceable diameter. Exact positioning understandablymakes clean, qualitatively faultless repair of the damaged intersection15 possible.

Incidentally, the application device 1 is a replaceable component of aremote-controlled device such as the pipe-repairing machine 18 shown inFIGS. 5 and 7 which, as already mentioned, has already been patented bythe same inventor. Thus, it is possible without difficulty to feed inthe compressed air to pump up the balloon 3 and to observe and controlthe insertion of the, sheathing from the outside by means of a videocamera 19 fitted on the pipe-repairing machine.

When the sheathing 4 is placed in its exact position, the balloon 3 ispumped up with compressed air. The pressure which consequently acts onthe sheathing causes a wire 11 (or more than one wire 11) to tear; thiswire/these wires had previously held the slit sheathing at the diameter6. The sheathing, which has been pre-tensed in this way, then suddenlyexpands and presses itself against the internal walls of the subsidiarypiping 8, which had been undamaged up to then. The expansion of thesheathing and its pressing against the internal walls of the subsidiarypiping 8 are supported by the pressure in the balloon 3, which continuesto rise somewhat at the same time. The sheathing 4 is now held in thisposition, because it has been coated all around its circumference withadhesive 17 (e.g. epoxy resin or another suitable two-componentadhesive) before entry into the piping. The adhesion points are freedfrom bacteria and unhealthy material by cleaning and mechanical surfacetreatment. In order to avoid a drying of the adhesion points, work ismainly done with wet adhesive glues. After the sheathing has beenapplied and put into position, the compressed air can be removed fromthe balloon 3; the application device is removed from the sheathing. Thefirst phase of the repair has been completed. (FIG. 3)

The second phase of the repair (FIG. 4) consists of the cavity 12between the sheathing 4 and the damaged intersection 15 being sprayedwith sealing mass 16. In this, a high-pressure nozzle 13 is used (FIG.4), which is either integrated into the application device 1 or fittedto the pipe-repairing machine already mentioned as a component part.When the damaged spot has been sealed all around, only routinesubsequent work must be carried out with the pipe-repairing machine(grinding etc.). The sheathing 4 is left there as a lost sheathing. Itcan be produced of non-rotting and chemically resistant material. Thisincludes stainless steels or plastics which are especially suited forsewer pipes. The use of rottable material is however to be considered:as the sheathing has fulfilled its purpose following the repair work andthe sealing mass has hardened, no damage is caused if, for example,nothing can be seen of it one year after the repair. The biologicallydecomposable plastics, which are still in the development phase, arerepresentatives of these rottable plastics, but there are certainlyother suitable materials. Incidentally, the sheathing 4 can have variouslengths, depending upon requirements, and can be produced from tubeswith a longitudinal slit or from pre-bent panels. Attention must merelybe paid to the fact that the spring constant of the material is largeenough for the sheathing 4 to expand well after the wire 11 has torn.

The new remote-controlled sheathing installation for inaccessiblemanifolds and junctions makes cheap and simultaneously efficient repairwork on damaged intersections possible, as the latter do not need to beexposed by excavation. Reliability is thus guaranteed by testedpipe-repairing machines with their (replaceable) components and newlydeveloped sealing masses being used.

For the sake of completeness, it must be mentioned that the sheathinginstallation described can also be carried out manually, should thedamaged spot be in an accessible pipe.

I claim:
 1. A device for remote-controlled installation of sheathing ina manifold, comprising:an application device which insertable into amain piping of the manifold, wherein the application device haspositioning means for positioning said application device on an internalwall of the main piping; an inflatable balloon extendable from saidpositioning means in the direction of the internal wall of the mainpiping; an air compressor connectable to said balloon; and an expandablesheathing, said sheathing being rolled into a pre-tensioned state aroundsaid balloon and held by at least one wire therearound; wherein saidballoon, together with said expandable sheathing placed over saidballoon and held tightly therearound by said at least one wire, isinserted into a junction of a branch piping of the manifold, and whereininflation of said balloon causes said at least one wire to break so thatsaid sheathing is released and thereby pressed against an interior wallof the branch piping as it springs open from its pre-tensioned state. 2.Device according to claim 1, wherein the screen is bent according to theangle of the internal wall of the main piping.
 3. Device according toclaim 1, wherein the screen protrudes across the junction of thesubsidiary piping.
 4. Device according to claim 1, wherein the balloonis produced of an inflatable rubber hose material.
 5. Device accordingto one of the claims 1, wherein the sheathing is slit along its entirelength and is compressed in such a way that the slit parts of the walloverlap.
 6. Device according to claim 1, wherein the sheathing isdisposable sheathing.
 7. Device according to claim 1, wherein theapplication device is fitted with a nozzle, in order to seal the cavitybetween the sheathing and the damaged parts of the pipe at the junctionby means of a sealing mass.
 8. Device according to claim 1, wherein theapplication device is connected to a remote-control device.
 9. Deviceaccording to claim 8, wherein the remote-control device is on apipe-repairing machine.
 10. Device according claim 1, wherein thesheathing is produced from an elastic material.